This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Background: Bocavirus is a genus of subfamily Parvovirinae, which includes bovine parvovirus (BPV), canine minute virus (CnMV) and the recently identified human bocavirus (HBoV). HBoV has been associated with lower respiratory tract infections in children, and has been suggested to account for as much as 5% of lower respiratory tract infections worldwide. Rationale: Currently, both virus and infectious DNA of HBoV are not available, characterization of these animal bocaviruses will eventually provide information to the genus Bocavirus in general. Study question: Understanding the epidemiology of HBoV infection in humans and the molecular basis how bocaviruses replicate in host cells. Outcome measures: Establish a serological method to detect antibodies against HBoV in sera and construct infectious clones of bocaviruses to dissect the roles of bocavirus proteins in viral replication.